Paolo Bartolomei

Cosmic background reduction in the radiocarbon measurements by liquid scintillation spectrometry at the underground laboratory of Gran Sasso

Radiocarbon measurements by two 1220 Quantulus ultra low background liquid scintillation spectrometers were performed at the underground laboratory of Gran Sasso and the Radiocarbon Laboratory of E.N.E.A.-Bologna to study the efficiency and background variations related to measurement sites. The same configuration setup, i.e. the same center of gravity of the 14 C spectrum (SQP(I) = 410 ± 1) was obtained in both instruments. Many different background and modern standards with pure analytical benzene were used and spectra for 40 one-hour periods were obtained. The data indicates a background reduction of approximately 65% between the surface and underground laboratories, with no differences in the efficiency. Recording similar efficiencies in both spectrometers is probably due to fairly identical photomultiplier characteristics. The cosmic noise reduction observed at the laboratory of Gran Sasso makes it possible to perform high precision 14 C measurements and to extend for these idealized samples the present maximum dating limit from 58,000 BP to 62,000 BP (5 mL, 3 days counting).

High-frequency depositional cycles within the late Quaternary alluvial succession of Reno River (Northern Italy)

Palaeosol-based correlations within the Late Pleistocene-Holocene alluvial succession along the Reno River, in the southern Po Plain, enabled the identification of depositional cycles falling in the sub-Milankovitch band. Each cycle, composed of overbank and fluvial facies capped by poorly to weakly developed palaeosols, is correlatable upstream to a single fluvial terrace in the Reno River valley and to an individual channel belt close to the valley outlet. Four cycles, dated to about 15-10 (c1), 10-5.5 (c2), 5.5-1.5 (c3) and

210Pb and 210Po concentrations in Italian cigarettes and effective dose evaluation

AbstractIt has been known for a long time that cigarette tobacco contains naturally occurring radioactive nuclides such as 210Pb and 210Po. In this study, the concentrations of 210Pb and 210Po in the 10 most widely sold cigarette brands in Italy during the year 2010 were measured, and the effective dose to smokers has been calculated. The results of this study show that 210Pb concentration ranged from 11.6 to 20.0 mBq cig−1 with an arithmetic mean of 14.6 mBq cig−1, while the activity concentration of 210Po ranged from 13.1 to 19.0 mBq cig−1 with an arithmetic mean of 15.7 mBq cig−1, thus confirming previous results and showing that the radioactivity concentration was not reduced in the last few years. The annual effective dose for a typical smoker consuming 20 cigarettes per day ranged from an average of 55 &mgr;Sv y−1 to about 81 &mgr;Sv y−1. It is finally put in evidence the need to improve the knowledge about crucial data needed for accurate dose assessment deriving from the inhalation of both radioisotopes contained in the cigarettes, namely the dose conversion coefficients, which strongly depend on several parameters such as the inhalation speed through the mouth, the real fraction of radionuclide transferred from cigarette to mainstream smoke, the lung absorption behavior of the radioisotopes inhaled with mainstream smoke, and the AMAD of particles inhaled by smokers.

Solar Flare Particle Effects and Seasonal Radiocarbon Variations in Tree Rings of the Northern and Southern Hemispheres

Measurements of A14C and S13C, separately in early wood and late wood of two Mediterranean pine species, with a nearly year-long growth season, were made to better define possible solar flare particle effects. The measurements were made for suitable periods around the years of big flares (e.g., 1942, 1946, 1989) in Pinus pinea of the Adriatic area and Pinus halepensis from South Australia. We found that the 14C concentration is consistently greater in early wood than in late wood of the same growth ring and considerably higher in the Australian samples than in the European samples. The data so far reveal no evidence of solar-flare effect.

ENEA Radiocarbon Measurements III

This paper includes determinations of geological samples coming from the Emilia Romagna region (northern Italy) performed at the ENEA Radiocarbon Laboratory. These analyses were executed as part of the Geological Cartography (CARG) project aimed to realize a new Italian Geological Map.

Optimisation of radioxenon measurement for comprehensive nuclear test-ban treaty

ABSTRACT The international monitoring system (IMS) has been developed to verify compliance with the comprehensive nuclear test-ban treaty (CTBT) and radionuclide monitoring stations are the smoking gun for underground nuclear explosions identification. One of the main objectives of the verification regime is to improve the sensitivity of measurements providing background reduction and, as a result, decrease the minimum detectable activity (MDA) values. At this ENEA laboratory an anticoincidence system has been developed: the system is comprised of a high purity germanium (HPGe) detector surrounded by a low–background shield and two plastic scintillators able to detect coincident cosmic-ray interactions. Tests conducted with the anticoincidence system have shown a reduction of the Compton continuum that contributes to the spectrum background and the measured MDA values, compared to those obtained using the standard system, decreased for all the four radioxenon isotopes.

New developments in resonance photo-neutron spectroscopy

The threshold photo-neutron technique explores the process of resonant absorption of gamma-rays and the decay of the compound state by neutron emission. The authors examine, on the basis of currently obtainable experimental conditions, the class of nuclei and the characteristics which can be investigated to advantage by this technique. With reference to the Bologna facility, some improvements are discussed concerning the measurement of angular distributions, the efficiency and time properties of neutron detectors and the development of computer codes for data analysis.

A facility for resonance photo-neutron measurements

Abstract A facility is described for measurement of (γ, n) cross-sections and angular distributions, for neutron energies up to 0.5 MeV. For the photoneutron reaction on 25Mg it is shown that, in a measurement at different angles, a neutron peak due to 25Mg(γ, nl) can easily be distinguished from other peaks due to 25Mg(γ, n0).